Admission control The gatekeeper can control what endpoints join
and participate in the H.323 network. For simplicity, the gatekeeper can
be configured to allow all endpoints to join the H.323 network. Alternatively
for tighter security it can only admit a known list of endpoints.
The gatekeeper may also restrict endpoint participation by other settings
configured by the administrator, such as available bandwidth or number
of active endpoints. Although an H.323 network does not require a
gatekeeper, if a gatekeeper exists, all participants are required to use it,
allowing security to be enforced.